I have a three story detached house which uses a lot of energy, particularly in the winter. I'm looking to insulate the loft but I'm not sure which kind of insulation to go with. Glass wool seems like option, but a friend says she has some rigid foam insulation going spare, which is probably enough to cover my attic. What would be the best option to go with, or should I use another sort of insulation material?
Blown or batts. See HomeDepot for a comparison. Look at R-Value and height and depth. Also, both fiberglass and cellulose can iritate your lungs. So wear a respirator. Also check out the HomeDepot recommended R value for your zone. I would suggest cellulose. BTW, I DO NOT suggest buying from Home Depot or any other big box. Keep your purchases local if you can.